Thanks for this video! Although I am surprised that after 4 1/2 years nobody has pointed out that 9 isn't a prime number.

Thank you for taking the time! This is very useful as you are obviously measuring your room before you decide on how deep your wells should be. This is not a prime number QRD but the video still is very necessary because no one is explaining the math. Also the width of the well is just as important than the depth.

Thank you for your hard work on these presentations!

I love watching your videos, thx for all the info you put out . Its incredible how much I learned thx again.

This is the first video I have seen of your channel, and I must say, well done sir. Efficiently described and presented. It is exactly the information I was looking for mathematically and your last minute of the video made me notice my need for this in my studio space.

Incredible knowledge in all of your videos

Dennis you always do a great job with your videos! Thank you so much for the time you spend on the videos and thanks for creating great products!

Looking to build a quadratic diffuser. This is such great information. Thank you Dennis.

I try to watch all your videos because all of them are helpful . thank you ...

Very helpful video by the way. Thank you

Preaching the knowledge. Good stuff.

Hey Dennis,i want to ask you if were to put quadratic diffusers in a 3mx4.60m wooden studio for drums only will they have any effect??if so what else do you suggest that i should put and where to position them exactly..i am thinking of putting two vertical on the opposite wall of the drums and one horizontal on the sealing.thanks for you time

Thanks for another awsome video.

Amazing! Great channel this.

great video dennis

ill be building my BDA's in a couple weeks beginning with 6 units and im so tempted to build a diffusers just to get that real sound but alas, i have yet to meet the requirements to put them in place. Incidentally, is it proper to place diffusers on my front wall in front of all my BDA's?

Usage is CRITICAL LISTENING with voice and percussion. Thx

What material are you making the diffusers out of?

Well Explained:-) Thanks

Thanks for the great video as always. I have built your panels for several rooms with great success. Am trying to set up a small room and was wondering how far away from the diffuser panels does the listener have to be for them to be effective. In this case I am specifically talking about the qd7.

Thanks for your videos. I've learned a lot from all your content and website. One question; Well Width often seems to be left out of most conversations about these diffusers. And the online quadratic calculators seem to give a very small width compared to the ones i've seen with my eyes. What would the Well WIDTH be for the example given in this video? Thank you.

thanks bro!

Hi Dennis. Am just setting up my project studio space and thinking before I get into diffusion and bass traps, I might cover the walls (presently sheets of wood panel over drywall) with planks of pine wood. Is it better for the room acoustics for the planks to be vertical or horizontal, or does it not matter?

I teach acoustic also but I am nowhere nearly as good as you. Truth is I did take acoustic in my Music Production and Engineering program, not exclusively architectural acoustics. Many of your videos have helped me learn greatly and I can't wait to assemble a diffuser myself! A question though, are prime numbers something that tell me what frequency length this diffuser works with? Thanks so much!

for that particular quadratic diffuser (prime 7 example?) would you just run one of those directly behind you or do you stack them side by side? if you do put them side by side what dictates the amount that you stack side by side (with the diffuser running vertically) and I guess the same question for running them horizontally?

Hi, what is the proper displacement of quadratic diffuser in 12’x12’ room in relation of listening position? Thx

Best video ever. How wide should the wood itself be? 1/2 inch? 3/4 plywood? I want to use pine. Alder and cherry are too expensive.

For home theater room - if I place a P- 7 in the back wall so the seating should be 2 feet from the back wall? I came up with a number from your video "Sound Diffuser Placement - How To Position A Sound Diffuser"

Nice video. In this case, assuming the highest frequency diffused is 3385 Hz, is the well width half of the wavelength of 3385 Hz signal?

Any impact on the room sound with the high of the Q-Diffusor ? ... everything so far I have heard re is related to width and depth.

Where are the ideal places to put diffusers (and in comparison to acoustic foam panels)? ie front wall, side walls, rear wall? Is there a rule of thumb or ratio for diffusers to absorptive panels?

Because of this video I built two large panels using the QRD formula behind each speaker. I immediately noticed a wider soundstage but I’m missing height in the vocals. Do you recommend adding center panel? Vertical or horizontal? Thank you

So is it depth that matters most? Does width of the channels matter? Likewise does thickness of the wood matter?

How tall should a diffuser be assuming it will put on the floor. How much of the front wall, for example, should be covered with diffusers?

HI My room is 20 feet length. 17 feet wide and 10 feet in height... what diffuser should i use... its a living room... with sofa fabric and wooden floor. it has curtains on both right and left. and both other walls front and back are brick smooth walls with paint. and concrete roof. Please let me know what all can i do...

Cheers Dennis. Another cracking video. Can we have a vid showing where you would ideally position the diffusers and what prime number combinations work best in relation to room size and room usage? Hehehe If you can fit all that in one video :-) Im guessing prime number 7 relates to the 1"+2"+4"=prime number7? Another question.....i know youve talked about symetry in regards to speaker positioning.......alcoves. how best to cover them when brickwork is not really possible. I was thinking 18mm mdf the whole wall but what do i infill the voids with? I was thinking a good solid frame of 100x50 timber behind. Lots of it to prevent it sounding like a drum. What do you think? I kinda know your going to say find a good bricklayer :-) is mdf and timber not really good enough as a compromise? Another :-) at college and uni we were told yellow insulation felt for heat and pink for sound. A method to provide a good barrier would usually be something like a 100x50 frame set 50mm away from the wall and packed with pink felt. Layers of felt behind the timber stud frame should wrap under and round the four sides so the frame was sat on the felt. Fixed with wedges so no screws into the floor walls or ceiling. Then boarded with foam backed plasterboard usually 10mm thick plasterboard with 20mm of foam. What do you think? Our acoustics lectures were a bit thin on the ground......think we had about 4 hours worth. We got as far as a 70db drill in a room +another 70db drill doesnt add up to 140db. We did learn how to calculate the true levels. A medium sized log equation if my memory serves me well :-) Cheers Dennis. Youre a diamond

Thank you

hello Dennis, wondering if this sound diffusers would be efficient to a meeting room. Without mecanic sound, only peoples voice and chats. Cause the frequency of the human voice seem to be below de 800Hz frequency low limit capted by this especific diffuser. Do you have any suggestion to this acoustic problem? greetings from Brazil

Hey Dennis, ive a question that pertains to how diffusers work/are effective. Someone told me youre not supposed to lacquer your diffuser - whats the science behind this reasoning? Also; how does that translate to paint - if i were to paint my diffuser, instead of using oil, do i just avoid anything that is "lacquer" and stick to mat, or is there a special kind of colour/base that i should be looking at? Thanks, Jan :)

What about combining horizontal and vertical in one diffuser?

Sir would you use a vertical and horizontal at the same? What’s the norm?

Hey Dennis, Love you work. Question: I'm planning to buy the dynaudio bm15a for my homestudio. Option one is my bedroom The roomsize is about 15 square meters in total, and the height is 3,5 meters, and has the shape of a square. Option 2: The attic, size is about 25 square meters, height 4 meters, and has the shape of a triangle. Meaning the roofshape are not vertical. If you want i can send pictures of the 2 rooms, wich one would you choose? The speakers are known to be very good sounding but i'm wondering is it to big for my homestudio? Can i treat my room as such that they are a good fit in my room? Thanks Emir

I have two questions. What kind of effect has diffuser on lower frequencis than the 1/4 wavelength. Let's say qd 13 has lowest diffusion frequency of 280 hz. What effect has it on 250 hz or 200 hz? Second question: Is it possible to have too much diffusion in listening room or home theather - can it become overwhelming or too live at some point, or is it a matter of taste? Thank You.

Thanks for this video! may I ask a stupid question? How can I reduce 84 Hz echo in my room?

The diffusion pattern numbers 1 4 2 2 4 1 bear a similarity to the pattern for numbers for Pascal's Triangle. Can you talk a little bit about where to find more information on the theory behind this pattern, so I can dig further? Thanks in advance.

Are you telling people that "fine wall art" is not the same thing???? I love these people who make "diffusers" without knowing the theories required to make it functional. Thanks for the video!!

Hi. Im big fan of your videos and I have a question. Does this diffusers make difference to room sound pressure? Can i make better room frequency response with these diffuser?

Hi Dennis, you say that the well depth is always 1/4 wave lenth hence the depths vary for the different wells due to different cycles they target. But how about the well width which you say is half wave length, the wells seem to be all having the same well width. Can you explain? And for a control room would you make the diffusion in the rear all with the same well depth or is it ok to make some with 6" and some with 12"? (not regularly distributed) Thank you very much for your really explanatory videos. Cheers, Caspar

Are space coupling diffusers good to use on a back wall when the listening position is close to the back wall? How thick should the the diffuser frame be? Should it be placed on the wall or extend into the room an inch or two off the wall?

Hi Dennis, what's your opinion on fractal diffusers?

And what about Skyline Diffusor? Does it really work?

Very interesting! Are these diffusers only meant for small rooms? Or are they also used in big spaces, like a music hall?

Does this repeat after the 1"? 1,1,4?

Does it work the same with planar dipole speakers?

Hi ***** I answered your question about what sound diffuser material you should use in greater depth in last weeks Google Hangout. You can see my answer to your question here kzfaq.info/get/bejne/l559pciFq9GpiJs.html Hope it helps. Let me know if I can be of further assistance. Thanks Dennis

So it would work good for an audiophile in their home music listening room?

спасибо за субтитры!

You provide the well depths - but how wide is each well? On the real diffuser they look about 2 inches wide. Does it matter how wide they are? Do they all have to be the same width?

Hi, Dennis- My room is 19' x 14' with an 8' ceiling-- not a big room. Is there any point in putting a diffuser in there?

In theory could I cut all those numbers in half and it still be quadratic ? Example .5, 2,1,1,2, .5 ?

Wowww thats good

Where is the 7th well?

how is 1132'/s divided by .33' --3385 hz and not 3430 hz

Thank you for your videos. Have you seen the designs for quadratic diffusors which use frames that are hollow behind them rather than having solid walls between each well? These have an interesting aesthetic and they would be lighter due to less material. Something like this: kzfaq.info/get/bejne/mbGTZrBklcu0pZc.html I am curious if there are implications to this design and the lack of wall between the wells.

We’ll talk about that in another video

:)

JAAJAJ 9 IS A PRIME NUMBER AND THE EXAMPLE IS MOD 6 NOT MOD 7 COME ON

9 is not a prime number